After the relapse in Cornwall, we're back on track. R seems to be a fountain of emotion, honesty and regret. At times it is hard to watch, but it's even harder to work out whether what he's saying is genuine: he's a convincing actor.

Sometimes I find it more helpful to take everything he says as a lie. It brings a certain amount of clarity to any situation because I am focusing on only the things I know to be true, rather than the things I want to believe are true.

I am aware that through our relationship, I have been a pretty lousy listener, preferring to interject with advice and suggestions of a better approach to recovery. Recently, however, I am enjoying the more passive role of sitting back and letting R do the talking. He calls me at 5pm, just as I'm dishing up the children's supper: "I'm going to an AA meeting after work tonight. I've just found one that's relatively near. Probably full of City blokes, but worth a punt."

Then he tells me what he had for lunch, and how it was massive and filling, and that he'll probably pick up something small on the way home after the meeting so I shouldn't bother cooking for him. I notice that he talks a lot. Maybe it's nerves, now that I'm not interrupting his flow.

Later, while I'm bathing the boys, my daughter frames the doorway of the bathroom, all legs and adolescent petulance. "I'm starving. Dinner was disgusting."

This is normal. I ignore her. Then she says, "You told me that you would leave Dad if he started drinking again."

I'm not prepared for this conversation and shush her unfairly. All I'm really trying to do is keep her brother – the one who can sort of understand what we're talking about – from hearing. "We'll talk about this after I've put the boys to bed, darling."

Later is really quite late and it seems unfair to have such a loaded conversation just before my daughter goes to bed. It seems worse, though, for her to carry these heavy thoughts over into sleep.

"He drank last week. How do you know that he's not drinking behind your back, every night?" she asks, as I massage her feet.

"I don't," I reply.

"Well, how can you trust him then? How can you stay with someone you can't trust?"

Her direct approach is admirable, yet disarming, and I realise that she is asking me to redefine everything she has believed about long-term relationships, love and trust. When R and I married, my daughter who is from a previous relationship, barely reached our knees but she understood the vows. She asked to be lifted high on to R's shoulders as we were pronounced man and wife. Now everything seems like a horrendous lie.

"Well?" she persists.

"I can't. I can't trust him and neither should you. But we can still love him."

At the same time as telling her to accept that he is dishonest, I am asking her to show him compassion. She is a child and shouldn't have to display anything that she doesn't feel.

I am a fraud. She pulls her foot away from my hand in anger and tells me she wants to go to sleep. I try to rouse some emotion in my body, in my voice, but I feel detached from all of this. In my attempt to protect my daughter's beliefs and guard her from something – I'm not entirely sure what – I'm unable to connect with the present situation.

"I love you. I know this is confusing and must hurt, but I love you and Daddy loves you."

The word love never sounded so frail, and it is a cheap payoff to a conversation that never even dipped below the surface. But I know my daughter. She wants me out of her room and I need to think about how to deal with this intelligently before resuming our talk tomorrow.

A key turns in the front door as I come down the stairs. R stands in the hall with a smile on his face and a kebab in his hand. I look at his eyes for signs of drink, but they are still so I smile back. I ask him to go upstairs to kiss our daughter goodnight, a poor attempt to assuage my growing sense of guilt. She is rightly furious with both of her parents and it is doubtful that a kiss will make anything better tonight.